It looks like you're missing a portion of the original recipe for the "Marvelous Meatloaf," specifically the amounts of ingredients like the garlic powder in teaspoons. To provide an accurate answer about how much garlic powder Marci needs when scaling down the recipe, I’d need the full details of the original recipe.
Please provide the total amount of garlic powder in teaspoons from the original recipe, and then I can help you determine how much Marci needs if she's making a smaller portion.